Plasticized urea-formaldehyde resin



[Patented June 1-5, 1948 .4483 PLAS'HOIZED URlA-FORMALDEHYDE RESIN James llanald Alexander, Donald Barton. and Frederic Hansmann. Bolton, England. asaignors to William Walker and Sons Limited. Bolton.

England, a British company No Drawing. Application November 27, 1943, Se-

rial No. 512,022. In Great Britain December selenium-ass) This invention relates to amino-formaldehyde resins and especially to those made from urea. thiourea, melamine and the like. Y

It is well known that such resins. especially in aqueous solution. dry out to give very hard and brittle products. The brittleness of these resin condensation products is a disadvantage and precludes their use for many applications.

In the case or amino-formaldehyde resins soluhis in organic solvents, the problem oi plasticisers isnotas diiilcultas in the case of the watersoluble types oi resins. In the former case oils, such as castor oil. cellulosenitrate plasticisers such as butyl phthalate. and tricre'syl phosphate.

as well as many synthetic resins oi the alkyd ll known as alkalis. which have excellent plasticising properties for the above resins.

Example A 50% aqueous solution ot a urea iormaldehyde resin is prepared by condensing urea and commercial aqueous formaldehyde in the proportions or 1 mol. of urea to 2% molecules of formaldehyde. The condensation is carried out at 100 C. for 1 hour at pH 2.5 and then for 1 hour at pH 4.5.

To 10 parts byweightol theabovc solution are added 6 parts by weight of a 50% aqueous-schition of sodium lactate. The mixture is then dried under reduced pressure for three days at 30 C.

no tendency to crack or craze on further drying.

The resin without the addition of sodium l ctate dries out to a brittle solid which cracks and iinall! disintesrltcs.

The proportions of lactate to be used depend on the particular application for which the amino resin is required. Thus for an adhesive for laminating leather. 2 parts lactate only are required for 100 parts amino resin. but in order to prevent shrinkage and cracking in an adhesive ior wood, it is necessary to use 15 parts lactate for 100 parts resin.

The lactate is thus usually a minor proportion of the whole. The lactate is preierably less than 25% by weisht oi the resin.

We declare that what we claim is:

1. A tough plastic resin comprising a major proportion of urea-formaldehyde resin and a lesser proportion of sodium lactate.

2. A tough plastic resin comprising urea-formaldehyde resin combined with trom .2 to 15 per centum of sodium lactate.

3. A composition oi matter having a major Pr portion of a urea-formaldehyde resin and a minor proportion oi an alkali lactate.

4. A composition of matter having a major proporticn eta urea-formaldehyde resin and from 2 to 26 per cent by weight of an alkali lactate.

Jam RANALD ALEXANDER. DONALD BURTON. mapmc HAUSMANN.

aeraaancss crran The following references are oi record in thefile oi this patent:

UNITED srs'rns PATENTS Wertheim. Textbook oi Organic Chemistry. 2d 

